1. Field of the Invention
The present invention relates to a sound signal processing apparatus for adjusting a sound volume and a sound signal processing method for use with the sound signal processing apparatus.
2. Description of the Related Art
Various sound playback apparatuses having a function for correcting output sound by suppressing the volume of output sound are known. Such a sound volume correction function prevents, for example, the occurrence of distortion due to an excessive level. Furthermore, sound is not output at a larger volume than necessary due to an inadvertent sound volume operation, and a user does not experience annoyance. Also, a sound output circuit system, a speaker, etc., are prevented from being destroyed by an excessive signal input (see, for example, Japanese Unexamined Patent Application Publication Nos. 2001-77645 and 2002-84589).
In a case where the above-described sound volume correction function is mainly provided for the purpose of preventing distortion of sound and protecting circuits, etc., when, for example, a configuration in which the signal level is simply limited to a particular fixed signal level or lower, there are cases in which, for example, the sound volume suppression is more than necessary, and the sound volume sensation expected by the user is deteriorated. This situation leads to, for example, the sound being regarded as an unattractive playback sound by the user.
Therefore, the control for sound volume correction is required to be properly performed in such a way that both the distortion prevention effect and the obtainment of sufficient sound volume sensation from a hearing point of view can be managed. Also, an algorithm for such sound volume correction is preferably as simple as possible when the circuit size, the amount of memory usage corresponding to the size of a program, etc., are taken into consideration.